Oil filter for construction machine and assembling method thereof

ABSTRACT

The prevent invention provides an oil filter comprising a filter element housed in a casing, the filter element being formed of two or more cylindrical element pieces piled on top of another in the height direction and attachably and detachably connected through connecting members. Accordingly, the efficiency in each of manufacture, stock control and storage of the filter element can be improved, and the cost can be also reduced.

BACKGROUND OF THE INVENTION

[0001] 1. (FIELD OF THE INVENTION)

[0002] The present invention relates to an oil filter provided in ahydraulic circuit of a construction machine and an assembling methodthereof.

[0003] 2. (DESCRIPTION OF THE RELATED ART)

[0004] An oil filter is provided in a return circuit for returning aworking fluid for driving the hydraulic actuator of a hydraulicexcavator or the like, whereby dust or the like in the working fluid isremoved to purify the working fluid. The flow rate of oil in a hydrauliccircuit is varied depending on the size of excavator, so that filterelements of various sizes differed in filtration area are requireddepending on the flow rate.

[0005] Therefore, manufacturers had to manufacture various types ofelements, and both manufacturers and users had to store various types ofelements for replacement. This introduces a problem in stock controlsuch as stock adjustment, in addition to an increase in manufacturingcost, because the shipping state is dispersed every type of elements.Further, the necessity of storing the filter elements by different partnumbers every size causes the problem that the space efficiency ofstorage shelves is deteriorated, and the necessity of changing thestorage space of storage shelves every element size leads to problems ofpoor storage efficiency and an increased storage cost.

SUMMARY OF THE INVENTION

[0006] The present invention thus has an object to provide an oil filterfor a construction machine capable of improving efficiencies in themanufacture, stock control and storage of a filter element, and anassembling method thereof.

[0007] The oil filter for construction machine of the present inventionis characterized by that a filter element is constituted by piling twoor more element pieces on top of another in the height direction. Thisoil filter comprises a casing provided with an oil inflow port and anoil outflow port, and the filter element housed in the casing, and thefilter element is formed of two or more element pieces piled on top ofanother vertically. The element pieces consist of single element piecesor a small variety of element pieces in size.

[0008] According to this, since various sizes of filter elements can beconstituted by piling two or more element pieces on top of anothervertically or in the height direction, the manufacture, stock controland storage of this filter element is facilitated more than in the pastby much, and the efficiency in each of manufacture, stock control andstorage can be remarkably improved to reduce the cost.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009]FIG. 1 is a sectional view of an oil filter according to a firstembodiment of the present invention;

[0010]FIG. 2 is a sectional view of the oil filter of FIG. 1 wherein thefilter element is formed of one element piece;

[0011]FIG. 3 is a partially enlarged view of FIG. 1;

[0012]FIG. 4 is a sectional view showing the storage state of theelement pieces constituting the filter element of the present invention;

[0013]FIG. 5 is a sectional view of an oil filter according to a secondembodiment of the present invention: and

[0014]FIG. 6A-6E are views showing configuration examples of the filterelement in the oil filter of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] The structure of the oil filter according to the first embodimentof the present invention will next be described in reference to FIG.1-6E. This structure is only one embodiment of the present invention,and the present invention is never limited thereby.

First Embodiment (Refer to FIG. 1-3)

[0016] In FIGS. 1 and 2, the oil filter of the first embodiment isconstituted as follows. A casing 14 comprises a metallic cylindricalvessel 11 having an oil inflow port 12 as inlet provided on the sidewall and an oil outflow port 13 as outlet provided on the bottom wall. Afilter element 15 as a filter member formed of cellulose fiber, glassfiber or the like is housed in the casing 14. The element 15 is arrangedso that its outside surface is located on the oil inflow side and theinside surface on the oil outflow side. The oil filtered and purified bythe element 15 is discharged through the oil outflow port 13 provided inthe bottom of the casing 14, and returned to an oil tank. The element 15is arranged, as shown in FIG. 1, so as to cover the oil outflow port 13.

[0017] As the shape of the element 15, tubular and cylindrical shapescan be exemplified, but the shape is never limited by them.

[0018] In the same drawings, denoted at 16 is the lid of the casing 14,17 is the lid of the filter element 15, and 18 is a spring exemplifiedas an elastic member provided between both the lids 16 and 17 to fix thefilter element 15 in the casing 14.

[0019] In the oil filter shown in FIG. 1, the filter element 15 isconstituted by piling two element pieces 19 of one type uniform in size(height dimension and diameter dimension) and in material on top ofanother in the height direction (vertical direction). Hereinafter, thedescription is made for the example using two element pieces, but thenumber of element pieces or the kind of materials are not limited bythis. Of course, the filter element 15 can be constituted also by thesingle use of the element piece 19 as shown in FIG. 2 in case of smallflow rate of oil.

[0020] Since the filter element 15 is constituted by using at least oneor more of element pieces 19 of the same type, the manufacture, controland storage of the filter element 15 can be performed in unites of theelement pieces 19.

[0021] In this case, the manufacture of only one type of element pieces19 suffices for a manufacturer, and the filter element 15 can beassembled by piling a required number of them on top of anotheraccording to a desired filter element size. Of course, the single use ofthe element piece 19 might be sufficient depending on the desired size.

[0022] Further, the stock control and storage of only this type ofelement pieces 19 suffice for both manufacturers and users.

[0023] Accordingly, the manufacture, stock control and storage of thefilter element 15 is facilitated by far, compared with at the time whenit was manufactured, stock-controlled and stored every size. Therefore,the cost in each stage of manufacture, stock control and storage can bereduced, and efficiencies of stock control and storage are remarkablyimproved.

[0024] In storage, for example, the element pieces 19 can be stored in acommon storage shelf 20 fitted to the size of the element pieces 19 witha common part number attached thereto, as shown in FIG. 4. The storagespace can be thus wisely used, and the troublesome sorting work by everysize can be dispensed with. From the point of storage control, sincethere is no difference in shipping quantity every size as in the past, atrouble or risk for storage adjustment can be eliminated.

[0025] In the oil filter of FIG. 1, both the mutually piled elementpieces 19 and 19 are attachably and detachably connected to each otherthrough ring-like connecting plates 21 and 22 mounted on the respectiveconnecting faces by caulking or the like.

[0026] Namely, as extendedly shown in FIG. 3, a male screw part 21 a isthreaded on the upper connecting plate 21 mounted on the lower surfaceof the upper element piece 19, and a female screw part 22 a is threadedon the lower connecting plate 22 mounted on the upper end surface of thelower element piece 19. Both the element pieces 19 and 19 are attachablyand detachably connected to each other through both the connectingplates 21 and 22 by the male and female screw parts 21 a and 22 a.

[0027] The inner and outer diameter dimensions of both the connectingplates 21 and 22 are set equal to those of the element piece 19.

[0028] A ring-like seal member 23 is further provided on the lowersurface of the upper connecting plate 21. This seal member 23 preventsthe leak of oil from the screw joining part of both the connectingplates 21 and 22 (between both the element pieces).

[0029] The attachable and detachable connection of both the elementpieces 19 and 19 provides the following effect. When the passing flowrate of oil is different between both the element pieces 19 and 19 bythe positional relation between the oil inflow port 12 and oil outflowport 13 of the casing 14 to cause a difference in clogging state betweenboth the element pieces 19 and 19, for example, both the element pieces19 and 19 are separated once, and their positions are interchanged,whereby the clogging state can be equalized to improve the aggregativelife of the filter element 15.

[0030] Since the both the element pieces 19 and 19 are screw-joinedthrough the connecting plates 21 and 22, the assembling and separationof the filter element 15 can be easily performed only by screw fasteningand loosening operations.

[0031] Further, since the connecting part is never protruded to theinside and outside of the element because of screw joining, there is nofear of the inhibition of oil flow by the connecting part.

[0032] In the structure of FIG. 1 where both the element pieces 19 and19 are attachably and detachably connected to each other through theconnecting plates 21 and 22, when the total height dimension of thefilter element 15 is X, an effective height dimension for performing thefiltration effect is H (not shown), the height dimension of both theelement pieces 19 and 19 is h, and the height dimensions of theconnecting plates 21 and 22 are y1 and y2, respectively, the followingrelational equations are established.

H=2h  (1)

X=2h+y1+y2  (2)

Second Embodiment (Refer to FIGS. 5 and 6A-E)

[0033] In the second embodiment, the same reference mark is given to thesame part as in the first embodiment to omit the duplicate description.

[0034] In the first embodiment, the effective height dimension H of thefilter element 15 can be adjusted in an integral multiple of the heightdimension h of the element piece 19. When it is necessary to furtherextend the range of size adjustment according to the flow rate of oil,the second embodiment is preferred.

[0035] In the second embodiment, as shown in FIG. 5, the filter element15 is constituted by combining a proper number (one each in the drawing)of element pieces 19A and 19B of two types with differences in heightdimension (h1, h2), wherein the element piece 19A is a small piece, and19B is a large piece longer than 19A.

[0036] In this case, various sizes of filter elements can be constitutedby use of only two types of element pieces 19A and 19B as shown in FIG.6A-6E. Namely, FIGS. 6A and 6B show structures consisting of singlebodies of pieces 19A and 19B, respectively. FIG. 6C shows a structure bycombination of two small pieces 19A, FIG. 6D shows a structure bycombination of one small piece 19A and one large piece 19B (the exampleof FIG. 5), and FIG. 6E shows a structure consisting of only two largepieces 19B. Accordingly, five element sizes H1 (=h1), H2 (=h2), H3(=h1×2), H4 (=h1+h2), and H5 (=h2×2) can be obtained at the lowest.

[0037] Therefore, the range of size adjustment can be extended by far,compared with the first embodiment.

[0038] The size or type of element pieces may be further increased so asto respond to more minute size requests within the range never impairingthe merits in manufacture, stock control and storage.

[0039] The means for attachably and detachably connecting the elementpieces piled on top of another is not limited to the male and femalescrew joining method by the connecting plates 21 and 22 described in theabove embodiment. For example, flanges can be protrusively provided onboth the connecting plates to be mounted on both the pieces within therange never inhibiting the oil flow to mutually bolt both the connectingplates in the flanges.

[0040] According to the present invention, as described above, varioussizes of filter elements are constituted by using a single element pieceor a small variety of element pieces and piling two or more elementpieces on top of another in the height direction. Therefore, themanufacture, stock control and storage of the filter element arefacilitated more than in the past by far, and the efficiency in each ofmanufacture, stock control and storage can be remarkably improved toreduce the cost.

[0041] Suitably, connecting plates of ring shape or the like areprovided on the connecting faces of the element pieces, and theconnecting plates are connected to each other in the respective screwparts.

[0042] Accordingly, since the element pieces are mutually attachably anddetachably connected to each other, the element pieces are separatedonce, and their positions are interchanged when the passing flow rate ofoil is different between both the pieces, for example, because of thepositional relation between the oil inflow port and oil outflow port ofthe casing to cause a difference in the clogging state of each elementpiece, whereby the clogging state can be equalized to improve theaggregative life of the filter element.

[0043] Further, the element pieces may be joined to each other by maleand female screws.

[0044] In this case, the assembling and separation are facilitated.Since both the connecting plates are connected in the mutual screwparts, the connecting part is never protruded to the circumference ofthe element. Therefore, there is no fear of the inhibition of oil flowby the connecting part.

[0045] Further, a seal member may be provided between the connectingfaces of the element pieces.

[0046] In this case, the oil leak between the element pieces can besurely prevented in spite of the piling method.

[0047] An assembling method of oil filter according to the presentinvention comprises the following steps.

[0048] 1) manufacturing one type of cylindrical element pieces uniformin size;

[0049] 2) piling two or more element pieces on top of another in theheight direction to constitute a filter element; and

[0050] 3) housing the filter element in a casing provided with an oilinflow port and an oil outflow port to assemble an oil filter.

[0051] Another assembling method of oil filter according to the presentinvention comprises following steps.

[0052] 1) manufacturing two or more types of cylindrical element pieceswith differences in size;

[0053] 2) piling at least two types of element pieces on top of anotherin the height direction to constitute a filter element; and

[0054] 3) housing the filter element in a casing provided with an oilinflow port and an oil outflow port to assemble an oil filter.

[0055] One preferred embodiment of the present invention is disclosedabove, but the scope of protection of the present invention is neverlimited thereby.

We claim:
 1. An oil filter for a construction machine comprising: acasing provided with an oil inlet and an oil outlet; and a filterelement housed in the casing, the filter element being formed of two ormore element pieces piled on top of another vertically.
 2. The oilfilter according to claim 1 wherein the element pieces are uniform insize.
 3. The oil filter according to claim 1 wherein the element piecesdiffer in size.
 4. The oil filter according to claim 1 wherein theelement pieces are detachably connected to each other through connectingmeans.
 5. The oil filter according to claim 4 wherein the connectingmeans is formed of connecting plates and screw parts for mutuallyconnecting the connecting plates.
 6. The oil filter according to claim 4further comprising a seal member provided between each connecting faceof the element pieces.
 7. An assembling method of oil filter for aconstruction machine comprising the steps of: piling two or more elementpieces of one type substantially uniform in size on top of anothervertically to constitute a filter element; and housing the filterelement in a casing provided with an oil inlet and an oil outlet toassemble an oil filter.
 8. An assembling method of oil filter for aconstruction machine comprising the steps of: piling at least two typesof element pieces of two or more types with differences in size on topof another vertically to constitute a filter element; and housing thefilter element in a casing provided with an oil inlet and an oil outletto assemble an oil filter.